"Stupidity" is one of the biggest hindrances to successful COVID-19 testing in the U.S., according to billionaire philanthropist and Microsoft Corp. founder Bill Gates.

Gates continued his denouncement of how the U.S. government has handled the coronavirus. He called the country's testing system "insane" and said it now faced an unprecedented increase in deaths and a substantial waste of money.

Gates said most tests conducted in the country were totally useless because results took too long. Doctors and health authorities have to wait more than a week for COVID-19 test results - a disappointing reality considering time is of the essence, he said. "That is just stupidity," Gates said of the setbacks in clinical trial results. Tests in the U.S. today are complete "garbage and wasted," he said.

The U.S. has the most "worthless test results" in the world, Gates said on CNN's GPS program hosted by Fareed Zakaria. No other country has such testing insanity considering the billions of dollars being spent, Gates said.

Countries in Europe that battled the coronavirus outbreak earlier than the U.S. were able to conduct more effective containment, he said.

Spain, France and Italy were hit hard by the first wave of the pandemic and yet managed to prevent another wave from overwhelming their health care systems, Gates said.

However, in the U.S. authorities loosened up and opened cities for business. "They opened their bars...didn't wear masks and so those areas became the second wave," Gates said.

As of Monday, the U.S. had 5.08 million confirmed COVID-19 cases with 163,000 deaths, The New York Times reported.